Preliminary survey by staff overlooking Conservative polymath (11,3)
I believe the answer is:
'polymath' is the definition.
(I know that polymath can be written as Renaissance man)
'preliminary survey by staff overlooking conservative' is the wordplay.
I cannot quite understand how this works, but
'staff' could be 'man' (as in staffing or manning a particular place) and 'man' is found in the answer.
'conservative' could be 'c' (UK political abbreviation) and 'c' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for renaissance man that I've seen before include "Catholic intellectual" , "Wide-ranging intellectual" , "Person with many talents or interests" , "All-rounder" .)